Armored electrical cable



J. wERTzHElsER El' AL f ARMOBEDELECTRICAL. 'CABLE Oct. 29, 1935.

Filed may 15, 1935 l ATTORN E YS ANU INULAIUH.

Patented Oct. 29, 1935 UNITED STATES PATENT OFFICE ARMORED ELECTRICAL CABLE Joseph Wertzheiser, Newark, N. J., and Harry Charmoy, Long Island City, N. Y., assignors to Hillside Cable Co., Hillside, N. J., a corporation of New Jersey Application May 15, 1935, Serial No. 21,524

9 Claims.

'vide an armored cable of the above type, which may be expeditiously produced by automatic machinery, and which is substantially proof against electrical failure as for instance, due to tearing loose during installation of any insulation on the conductors that might have adhered to the armor sheath.

Another object is to provide an armored cable of the above type, with adequate protection along the entire exposed severed sharp edge of the sheath, and readily applied in installation of the cable, to preclude any possibility of cutting the insulation of the protruding outwardly turned conductors.

Another feature is the use of a split insulating bushing, to cover the exposed sharp cut edge of the sheath, said bushing having an advanced edge that is, a leading corner protruding longitudinally in advance of the rest of the bushing to facilitate anchorage between the metal sheath and the bonded protective cover, and tting preferably in the space left by removal of corresponding length of the outer unbonded insulating layer, the bushing being of peripheral length somewhat greater than the inner periphery of the sheath for overlapping at the split edges. In one embodiment, the insulating bushing is of generally helical form, the split ends being longitudinally displaced, so that after insertion of the anchoring end, the exposed helical rim may be depressed into a common plane, with the split edges wedged into overlapping relationship and the bushing thus frictionally held in place. In another embodiment, the insulating bushing is cylindrically wound and is of peripheral length greater than one complete convolution, the inner or advance rim at one of the split edges having a guiding projection to facilitate anchorage at said edge, the outer or exposed rim of the bushing having its overlapped ends interlocked.

In the present application, the protective bush- Ing is claimed per se and in its novel correlation with a conventional armored electric conductor. 'I'he novel features of the armored conductor herein disclosed, and the correlation therewith of a protective bushing are made the subjectmatter of a divisional application, Serial No. 43.530 filed October 4, 1935.

In the accompanying drawing, in which is shown one or more of the various possible embodiments of the several features of the invenvnon,

Fig. 1 is a perspective view of a length of the armored cable, with the protective bushing inserted, 5

Fig. 2 is a perspective view partly in longitudinal section, showing the removal of a portion of the outer protective layer,

Fig. 3 is a view similar to Fig. 2 showing one step in the application of the protective bush- 10- ing,

Fig. 4 is a view similar to Fig. 3, showing the iinal step in the application of the bushing,

Fig. 5 is a view in longitudinal cross-section showing the bushing applied, 15 Fig. 6 is a perspective view of the bushing as an article of manufacture, and

Fig. 'l is a view similar to Fig. 6 of an alternative embodiment of bushing.

Referring now to the drawing, there is shown go an armored cable illustratively with two conductors Ill and II, each covered by conventional insulation, illustratively braided covering I2. The conductors are shown enclosed in an insulating protective covering, which is preferably a g5 continuous spirally Wound sheet of paper I3 impregnated with Wax, preferably paraln. The width of the paper is illustratively three times the pitch at which it is wound, so that the completed sheath will be three-ply. In the con- 30 ventional process of fabricating the armored cable by winding the protective covering simultaneously with the armor sheath, the paraffin or other wax becomes suiiiciently softened to afford an adequate -bond of the various convolutions and to eifect a secure continuous insulating enclosure sheath, and this without the need for special application of any form of adhesive.

In addition to the bonded protective sheath, there is preferably employed, according to the 4,0 present invention, the further outer insulating covering I 4 of paper, devoid of wax or other adhesive, which is wound about the inner protective sheath I3. About the parts thus far described, is wound the conventional metal sheath 45 I5 comprising a strip of metal wound on a pitch substantially equal to its eifective width, the overlapping helical edges being crimped together at I6.

In the armored cable made as described, the 5 outer paper layer I4 is free from any adhesive! bond with respect to the sheath and substantial-y ly free of such bond with respect to the inner protective covering I3. Accordingly, no adhesive connection between the conductor or its protecu tive covering and the outer metal sheath can occur, so that in bending and manipulating the latter, there is no possibility oi tearing loose any oi the protective insulation, and electric failures from this cause are not apt to occur.

The protective bushing for the armor end II severed or cut in the installation of the cable, is preferably of fibre and may be of helical rather than cylindrical conformation and of peripheral length somewhat greater than one complete convolution. As best shown in Fig. 6, the split ends I 9 and I9 of the fiber bushing B are displaced longitudinally of the bushing along a pitch such that the trailing end 2U of the leadlng edge I9 overlaps the leading end 2| of the trailing edge I8. The leading end I9' of the leading edge I9 constitutes a guiding conformation for ready installation of the bushing and the part of the bushing adjacent said leading edge I9 becomes wedged or anchored in place in the application of the bushing, as best shown in Figs. 3 and 4. 'I'he leading rim 22 of the bushing is preferably oi' pitch somewhat greater than that of the outer or trailing rim 23 as appears from the fact that the leading split edge I9 is longer than the trailing split edge I8. Preferably, the pitch of the leading rim 22 of the bushing is substantially equal to that of the helically wound sheath, and the trailing rim 23 which has an outwardly turned flange 2l is of somewhat lesser pitch.

In use of the device, after cutting or severing the sheath as at II adjacent the outlet'box or other terminal structure, the outer insulating layer I4 only is preferably removed down to a point slightly below the exposed end of the sheath, thereby to afford clearance. The exposed insulation covered conductors are now' readily caused to enter the split I9, I9 of the bushing which is then pushed along the protective sheath I3 to become anchored adjacent leading edge I9, as best shown in Fig. 3, preferably under the advanced end of the severed or cut edge I1. The bushing thus becomes securely wedged or anchored near its split edge I9 between the sheath I5 and the contiguous protective covering I9 of the conductors. Thereupon, by pressing downward on the exposed rim 23 of the bushing, said rim is caused to move generally at right angles to its oblique length so that it becomes both longitudinally and circumferentially wedged in place between the anchored edge I9' of the bushing and the enclosed conductors. Thus, as best shown in Fig. 4, the exposed helical rim 23 becomes depressed into substantially a circular rim, with the split ends I9 and I9 of the bushing in overlapped relation.

'I'he application of the bushing is quite expeditious, since it requires nothing more than the single manipulation of introducing the leading or anchoring end I9 with the thumb and then following with light pressure with the index and middle nnger on the trailing rim 23 to wedge it home.

I'he bushing thus securely wedged in place is eiective around the entire periphery of the sharp severed edge of the armor sheath, so that the construction avoids the objection to ordinary split insulating bushings, in which protection is substantially lacking at the region of the split. In the present construction, the split region is in fact of enhanced security, since a double layer of fiber is presented thereat.

While the particular form of bushing shown in Fig. 6 is desirable. it will be apparent that the anchoring conformation or entering lentitud(- nai bushing edge might be used without extending the helical rim for the entire periphery of the bushing and that the helical rim of the trail-r ing or outer edge might be dispensed with. Such constructions are embraced within the scope of certain of the broader claims herein.

A particular embodiment of such construction appears in Fig. 7, in which the bushing is cylindrically rather than helically wound, with the l split ends I8a and I9a in overlapping relation, the periphery of the trailing or exposed ange! rim 23a. of the bushing lying in a common plane even prior to installation, and the leading rim. 22a is circular for the major portion of its length,A 15 but presents an inclined extension or guiding tooth I9" corresponding to the conformation I9 in Fig. 6. The ange 24a of this embodiment preferably -terminates at 25, leaving an unilanged end adjacent edge I9, which end is straddled by 50 the extremity of the ilange 24a, as shown at 2B. In the embodiment of Fig. 7, the bushing ins herently remains in cylindrical conformation, and since the ange 24 straddles the trailing end of edge I9, the construction is interlocked.

It will thus be seen that there is herein described apparatus in which the several features of this invention are embodied, which in its action attains the various objects of the invention and is well suited to meet the requirements .y

of practical use.

As many changes could be made in the above construction and many apparently widely dii'- ferent embodiments of this invention could be made without departing from the scope thereof, 35 it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a Hunting sense.

Having thus described our invention, what we n claim as new and desire to secure by Letters Patent, is:

l. An armored electric conductor comprising an insulated wire, a protective covering of insulating material surrounding the wire, a me- 45 tallic sheath enclosing the protective covering, and an insulating split bushing having a leading corner protruding longitudinally in advance of the rest of the bushing at one edge oi' the split to facilitate introduction and anchorage .of said 50 edge against the inner wall of the metallic sheath. the edges of the said split bushing being in overlapped relation to facilitate wedging the other edge between the anchored edge and the protective covering, with the bushing completely en- 55 circling the contents of the armored sheath.

2. An electric conductor comprising an insulated wire core, a helically wound armored sheath about said core, an insulated split bushing having a. substantially helical edge presenting a leading corner protruding longitudinally in advance of the rest of the bushing at one edge of the split to facilitate pushing inward and anchoring of said edge at the cut end of said metallic sheath, the exposed rim of the bushing being 65 frictionally held in the sheath with the other edge substantially to overlap theexposed end of the anchored edge of the bushing.

3. An armored electric conductor comprising one or more insulated wires, an armor sheath 7o thereabout presenting an inner helical ridge, an insulating split bushing for protecting a cut end of said armor, the split edges of said bushing being displaced longitudinally thereof, thereby affording a helical inner rim and a helical outer u 3 ANU INULA Ul'i.

anchoring the bushing at the corresponding split edge against the inner wall ot the sheath, the protruding outer rim in home position being brought substantially into a circular plane, with the split ends o! the bushing i'rictionally held in substantially overlapping relation within the sheath.

4. A protective insulating split bushing for an armored electric conductor, said bushing presenting a helically wound sheet ot length slightly greater than a single convolution, and of pitch such that the outer rim of the leading end overlaps the inner rim of the trailing end, the inner rim of the leading end constituting a corner protruding longitudinally in advance o! the rest of the bushing and serving to guide the bushing for anchorage adjacent the leading split edge.

5. A protective insulating split bushing for an armored electric conductor, said bushing presenting a helically wound sheet oi' length slightly greater than a single convolution, and of pitch such that the outer edge oi.' the leading end overlaps the inner edge o1' the trailing end. the leading end atl'ording a leading corner protruding longitudinally in advance of the rest oi the bushing and serving for anchoring purposes, the outer or trailing rim having a reversely bent ilange.

6. A protective split bushing i'or an armored electric conductor oi peripheral length greater than a complete convolution, said bushing at one oi the split edges having a leading corner protruding longitudinally in advance of the rest of the bushing and serving as an entering guide for anchorage of the corresponding split edge, said split edge overlapping part of the other split edge.

7. An armored electric conductor comprising an insulated wire, a protective covering oi insulating materials surrounding the insulated wire,

a metallic sheath enclosing the protective covering and an insulating split bushing anchored at 10 one split edge against the inner wail of the metallic sheath, said bushing having an outturned ange at its outer rim, and of length slightly greater than the inner peripheryof the armor it is to protect and having the unfianged outer ex- 15 tremity near one lateral edge straddled by the end of the ange at the other edge.

8. 'I'he combination as claimed in claim 7 in which one of the split edges has an advanced corner of substantially the pitch of the spirally zo wound armor and the unflanged outer extremity is at the same edge as said anchored corner.

9. A protective insulating split bushing for an armored electric conductor, said bushing presenting a cylindrically wound sheet oi' length greater 2i than a single convolution, one of the split edges of said bushing being longer than the other and affording an extension tooth thereat for anchoring, the outer rim of the bushing having an outturned ange terminating short of said length- 80 ened edge and straddled by that end of the ilange at the opposite edge.

JOSEPH WERTZHEISER. HARRY CHARMOY. 

